style: minor refactoring

[Akim Demaille]

commit 6f344fbe1ba4bd3eaee4492a4caa4f1bee5bd72b
Author: Akim Demaille <address@hidden>
Date:   Mon Sep 24 06:31:54 2018 +0200

    style: minor refactoring
    
    * data/bison.m4: Formatting changes.
    * src/scan-code.l: Avoid loops, prefer standard string functions.
    (find_prefix_end): Be const correct.
    Avoid useless intermediate variables.
    (variant_add): Be const correct.
    (parse_ref): Prefer variable definitions to assignments.

diff --git a/data/bison.m4 b/data/bison.m4
index cd810501..adc17543 100644
--- a/data/bison.m4
+++ b/data/bison.m4
@@ -856,9 +856,9 @@ m4_define([b4_percent_define_check_kind],
     [b4_error([m4_default([$3], [complain])],
               b4_percent_define_get_loc([$1]),
               [m4_case([$2],
-                 [code], [[%%define variable '%s' requires '{...}' values]],
+                 [code],    [[%%define variable '%s' requires '{...}' values]],
                  [keyword], [[%%define variable '%s' requires keyword values]],
-                 [string], [[%%define variable '%s' requires '"..."' 
values]])],
+                 [string],  [[%%define variable '%s' requires '"..."' 
values]])],
               [$1])])])dnl
 ])
 
diff --git a/src/scan-code.l b/src/scan-code.l
index 828ba9ff..f692fc10 100644
--- a/src/scan-code.l
+++ b/src/scan-code.l
@@ -215,10 +215,7 @@ is_dot_or_dash (char ch)
 static inline bool
 contains_dot_or_dash (const char* p)
 {
-  for (; *p; ++p)
-    if (is_dot_or_dash (*p))
-      return true;
-  return false;
+  return p[strcspn(p, ".-")] != '\0';
 }
 
 /* Defines a variant of a symbolic name resolution. */
@@ -277,26 +274,21 @@ variant_table_free (void)
   variant_table_size = variant_count = 0;
 }
 
-static char *
-find_prefix_end (const char *prefix, char *begin, char *end)
+static char const *
+find_prefix_end (char const *prefix, char const *cp, char const *end)
 {
-  char *ptr = begin;
-
-  for (; *prefix && ptr != end; ++prefix, ++ptr)
-    if (*prefix != *ptr)
-      return 0;
-
-  if (*prefix)
-    return 0;
+  for (; *prefix && cp != end; ++prefix, ++cp)
+    if (*prefix != *cp)
+      return NULL;
 
-  return ptr;
+  return *prefix ? NULL : cp;
 }
 
 static variant *
 variant_add (uniqstr id, location id_loc, unsigned symbol_index,
-             char *cp, char *cp_end, bool explicit_bracketing)
+             char const *cp, char const *cp_end, bool explicit_bracketing)
 {
-  char *prefix_end = find_prefix_end (id, cp, cp_end);
+  char const *prefix_end = find_prefix_end (id, cp, cp_end);
   if (prefix_end &&
       (prefix_end == cp_end ||
        (!explicit_bracketing && is_dot_or_dash (*prefix_end))))
@@ -433,31 +425,14 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
         }
     }
 
-  char *cp_end;
-  bool explicit_bracketing;
-
-  if ('[' == *cp)
-    {
-      /* Ignore the brackets. */
-      for (cp_end = ++cp; *cp_end != ']'; ++cp_end)
-        continue;
+  bool const explicit_bracketing = *cp == '[';
 
-      explicit_bracketing = true;
-    }
+  if (explicit_bracketing)
+    ++cp;
   else
-    {
-      /* Take all characters of the name. */
-      for (char* p = cp; *p; ++p)
-        if (is_dot_or_dash (*p))
-          {
-            ref_tail_fields = p;
-            break;
-          }
-      for (cp_end = cp; *cp_end; ++cp_end)
-        continue;
+    ref_tail_fields = cp + strcspn (cp, ".-");
 
-      explicit_bracketing = false;
-    }
+  char const *cp_end = strchr (cp, explicit_bracketing ? ']' : '\0');
 
   /* Add all relevant variants. */
   {